Together with Jim Blevins and Petar Milin, I will be co-editing a new series, Morphological Investigations, published through Language Science Press. We are inviting cross-disciplinary contributions, ranging from detailed descriptive studies through to quantitative analyses, simulations and models of learning and use. For more information, please consult the open call for submissions.

The team’s ageing research features today on BBC Radio4’s Frontiers, a programme “exploring new ideas in science and meeting the scientists and researchers responsible for them”. The episode can be streamed here.

Geoff Watts investigates the latest thinking about our brain power in old age.

He meets researchers who argue that society has overly negative views of the mental abilities of the elderly – a dismal and fatalistic outlook which is not backed up by recent discoveries and theories.

Geoff talks to Professor Lorraine Tyler who leads a large study in Cambridge (CamCAN) which is comparing cognition and brain structure and function in 700 people aged between 18 and 88 years old.

He also meets scientists and participants involved in an unique study of cognition and ageing at the University of Edinburgh. It has traced hundreds of people who were given a nationwide intelligence test as children in 1932 and 1947. Since the year 2000, the study has been retesting their intelligence and mental agility in their 70s to 90s. The Lothian Birth Cohort study is revealing what we all might do in life to keep our minds fast and sharp well into old age.

One new and controversial idea holds that cognitive decline is in fact a myth. A team in Germany, led by Michael Ramscar, argues that older people perform less well in intelligence and memory tests because they know so much more than younger subjects and not because their brains are deteriorating. Simply put, their larger stores of accumulated knowledge slow their performance. Their brains take longer to retrieve the answers from their richer memory stores.

The journal Psiholohija has just published Michael’s paper exploring the ways in which morphological prefixes and suffixes promote different kinds of learning.

In short, while prefixes tend to make the lexical items that follow them more predictable in context, suffixes tend to make the lexical items they follow cohere more, increasing the semantic similarity between them.

Provider Magazine has just published a Q&A with Michael on the myth of cognitive decline. Michael discusses the cultural origins of the myth, why overturning it may contribute to the social good, and the public’s reaction to this research. A brief excerpt:

“the myth has its roots in the way people have tended to think about our minds historically—and in the way that people often still tend to think about their minds. …just as learning to think about our bodies as part of the natural world has helped people understand how to better take care of their physical health, thinking about our minds as part of the natural world can help us make sense of the changes we experience as our minds grow older. “

In light of the recent press coverage of our ageing work, Michael has started a new blog, to provide more detailed coverage of our research program. The inaugural post — What happens to our minds and memories in healthy ageing? — is now live.

As adults age, their performance on many psychometric tests changes systematically, a finding that is widely taken to reveal that cognitive information-processing capacities decline across adulthood. Contrary to this, we suggest that older adults’ changing performance reflects memory search demands, which escalate as experience grows. A series of simulations show how the performance patterns observed across adulthood emerge naturally in learning models as they acquire knowledge. The simulations correctly identify greater variation in the cognitive performance of older adults, and successfully predict that older adults will show greater sensitivity to fine-grained differences in the properties of test stimuli than younger adults. Our results indicate that older adults’ performance on cognitive tests reflects the predictable consequences of learning on information-processing, and not cognitive decline. We consider the implications of this for our scientific and cultural understanding of aging.

Gregory: “Is there any other point to which you would wish to draw my attention?”

Holmes: “To the curious incident of the dog in the nighttime”.

Gregory: “The dog did nothing in the nighttime”.

Holmes: “That was the curious incident”.

–Sir Arthur Conan Doyle

For more puzzles on learning, morphology, and negative evidence, we turn to the abstract:

As children learn their mother tongues, they make systematic errors. For example, English speaking children regularly say “mouses” rather than “mice”. Because children’s errors aren’t explicitly corrected, it has been argued that children could never learn to make the transition to adult language based on the evidence available to them, and thus that learning even simple aspects of grammar is logically impossible without recourse to innate, language specific constraints. Here, we examine the role children’s expectations play in language learning, and present a model of plural noun learning that generates a surprising prediction: At a given point in learning, exposure to regular plurals (e.g. rats) can decrease children’s tendency to overregularize irregular plurals (e.g. mouses). Intriguingly, the model predicts that the same exposure should have the opposite effect earlier in learning. Consistent with this, we show that testing memory for items with regular plural labels contributes to a decrease in irregular plural overregularization in six-year-olds, but an increase in four-year-olds. Our model and results suggest that children’s overregularization errors both arise and resolve themselves as a consequence of the distribution of error in the linguistic environment, and that far from presenting a logical puzzle for learning, they are inevitable consequences of it.

This summer, we have two new papers coming out on early learning and development.

In Child Development, there’s an article on Dual routes to cognitive flexibility, which explores how three-year olds engage in flexible, goal-oriented behavior, in the absence of a mature prefrontal cortex.

Cognitive control, the ability to align our actions with goals or context, is largely absent in children under four. How then are preschoolers able to tailor their behavior to best match the situation? Learning may provide an alternative route to context-sensitive responding. This study investigated this hypothesis in the Dimensional Change Card Sort (DCCS), a classic test of cognitive control that most under-fours fail. A training intervention based on learning theoretic principles proved highly effective: Three-year-olds who learned about DCCS rules and game contexts in a card-labeling task, subsequently transferred this knowledge to sorting in the DCCS, passing at more than 3 times the rate of controls (N = 47). This surprising finding reveals much about the nature of the developing mind.

The question of how children learn the meanings of words has long puzzled philosophers and psychologists. As Quine famously pointed out, simply hearing a word in context reveals next to nothing about its meaning. How then do children learn to understand and use words correctly? Here, we show how learning theory can offer an elegant solution to this seemingly intractable puzzle in language acquisition. From it, we derived formal predictions about word learning in situations of Quinean ambiguity, and subsequently tested our predictions on toddlers, undergraduates, and developmental psychologists. The toddlers’ performance was consistent both with our predictions and with the workings of implicit mechanisms that can facilitate the learning of meaningful lexical systems. Adults adopted a markedly different and likely suboptimal strategy. These results suggest one explanation for why early word learning can appear baffling: Adult intuitions may be a poor source of insight into how children learn.

Last week, Michael served as a workshop panelist at “What Can We Do With 500 Billion Words?”, a mini-conference that brought together linguists and learning theorists, organized by lab alum Melody Dye and Prof Colin Allen. His presentation is now available for download.